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Biomedical subjects

P Martelli

Publications and source records attributed to P Martelli.

At least 19 recordsLinked to original sources
PubMed2006

Optical signal-to-noise ratio measurement by optical homodyne tomography.

An all-fiber optical homodyne tomography setup is introduced that measures the optical signal-to-noise ratio through reconstruction of the photon statistics. The scheme described has been conceived for applications to optical communications. In particular, the signal-to-noise ratio has been evaluated at lambda= 1.55 microm as a function of the received power. From the experimental data, in the case of optically amplified signals, the amplifier noise figure can be estimated.

Journal Article↗
PubMed2006

Antibody response to Mycoplasma hyopneumoniae infection in vaccinated pigs with or without maternal antibodies induced by sow vaccination.

Vaccination with bacterins is an important tool for the control of Mycoplasma hyopneumoniae infection of pigs. Because such vaccination often involves piglets that have suckled M. hyopneumoniae antibody-positive dams it is important to understand the effect of pre-existing (passively acquired) antibody on vaccine-induced immunity. To investigate this issue experimentally, 20 sows that were seronegative for M. hyopneumoniae were selected from a M. hyopneumoniae-infected herd and then randomly allocated to one of four treatment groups (five sows/group): Group A, vaccinated sows/vaccinated piglets; Group B, vaccinated sows/non-vaccinated piglets; Group C, non-vaccinated sows/vaccinated piglets; Group D, non-vaccinated sows/non-vaccinated piglets. Sows (Groups A and B) were vaccinated 14 days before farrowing and seroconverted within the next 14 days. Conversely, none of the non-vaccinated sows was seropositive at farrowing. Piglets (Groups A and C) were vaccinated when they were 7 days of age. Regardless of treatments none of the piglets had any evidence of an active immune response until many of those of Groups A and C and a few of those of Groups B and D seroconverted after it had been shown that at least some pigs of all groups had been naturally infected with a field strain of M. hyopneumoniae. This pattern of immune responsiveness (i.e. the collective results of Groups A, B, C and D) suggested that vaccination of pigs had primed their immune system for subsequent exposure to M. hyopneumoniae, and that passively acquired antibody had little or no effect on either a vaccine-induced priming or a subsequent anamnestic response. According to the statistical analysis sow serological status did not interfere with the antibody response in early vaccinated piglets. In conclusion, the results pointed out that early vaccination of piglets may assist M. hyopneumoniae control independently from the serological status of sows.

Animals↗
PubMed2005

Increased phospholipase activity in Helicobacter pylori strains isolated from patients with gastric carcinoma.

PURPOSE: Phospholipase activity, one of Helicobacter pylori pathogenicity factors, has not been investigated enough, so far, although it may induce a remarkable damage to the gastric mucosa. In the present work, we have compared the whole phospholipase activity of H. pylori strains isolated from patients with gastric carcinoma with that of strains isolated from dyspeptic patients without gastric carcinoma. METHODS: We measured the phospholipase activity of one distinct H. pylori colony isolated from each of 10 patients with gastric carcinoma and 10 controls, dyspeptic patients without endoscopic and histological signs of gastric carcinoma. We also determined the phospholipase activity of 20 additional strains isolated from different areas of neoplastic and non-neoplastic tissue of two patients with gastric carcinoma, the cagA and vacA positive G27 and 328 wild strains and their respective vacA and cagA negative isogenic mutants. The whole phospholipase activity of strains was determined by measuring the release of (14)C-labeled palmitic acid from the radioactive l-3-phosphatidylcholine, 1,2-di[1-(14)C]palmiloyl substrate; results were expressed in pmol of palmitic acid per mg of protein. RESULTS: H. pylori strains isolated from patients with gastric carcinoma had levels of phospholipase activity significantly higher than those of strains isolated from controls (99.37 [S.D. 40.45] versus 34.46 [S.D. 16.46], P<0.001). In patients with gastric carcinoma, the mean phospholipase activity of strains isolated from neoplastic tissue was similar to that of strains isolated from non-neoplastic tissues (123.02 [S.D. 44.36] and 115.77 [S.D. 81.48], respectively. Interruption of cagA gene caused a ca. 20% reduction of phospholipase activity (36.38 versus 45.22 of the wild strain); that of vacA caused no reduction of phospholipase activity (26.53 and 25.37 of the wild strain). CONCLUSIONS: The infection by H. pylori strains that produce high levels of phospholipase may increase the risk of developing gastric carcinoma. We hypothesise that indirect products of phospholipase activity, such as prostaglandins, leukotrienes and lysophospholipids, may mediate carcinogenesis.

Antigens, Bacterial↗
PubMed2004

Bee moth (Galleria mellonella) allergic reactions are caused by several thermolabile antigens.

BACKGROUND: Exposure and contact with bee moth (Galleria mellonella) larvae (Gm) can cause an allergic reaction both in anglers and breeders. We described the case of an amateur fisherman who experienced an allergic reaction using Gm but not using heat-treated Gm (h-Gm) (mummies). The aim of this study was to demonstrate by immunoblotting and radioallergosorbent test (RAST)-inhibition experiments the loss of allergenic epitopes in h-Gm extracts. METHODS: Galleria mellonella larvae and h-Gm were homogenized and extracted at 10% (w/v) in 0.5 M phosphate-buffered saline, pH 7.4 containing 0.5% NaN(3) for 16 h at 4 degrees C. Gm and h-Gm extracts were electrophoresed in a 10% polyacrylamide precast Nupage Bis-Tris gel at 180 mA for 1 h and the resolved proteins stained with 0.1% Coomassie brilliant blue and the molecular weight calculated. For the immunoblotting detection of allergenic components the resolved extracts were transferred onto a nitrocellulose membrane and incubated with the patient's serum. Bound specific-IgE was detected by peroxidase-conjugated anti-human IgE. RAST inhibition experiments were performed according to the Ceska method. RESULTS: The protein profile of Gm and h-Gm extracts resulted markedly different in number, intensity and the position of bands, indicating that heat-treatment modifies the chemical-physical characteristics of the protein contents. The Gm extract showed a strong-coloured band at 73 kDa and more than 20 components ranging from 12 to 133 kDa; h-Gm showed two main band at 77 and 38 kDa and about 15 faint bands between 20 and 133 kDa apparently without any correspondence to the bands present in the Gm extract. Immunoblotting with the patient's serum demonstrated several bands of reactivity with the Gm extract ranging from 20 to 100 kDa and no recognizable bands, but only a diffuse smear with h-Gm. When used in a RAST inhibition experiment the h-Gm extract demonstrated an inability to compete with the Gm one for the binding to patient's IgE serum. CONCLUSIONS: The h-Gm seems to lose the allergenic epitopes and has two advantages for anglers: to avoid new possible sensitizations as well as allergic symptoms in sensitized people, without interfering with their skills and satisfaction in their fishing performance.

Adult↗
PubMed2003

Preliminary evidence on the safety of ICSI with testicular spermatozoa in HCV-infected male: a case report.

An infertile couple with a hepatitis C (HCV) RNA-positive male came to our attention. We were not able to perform an assisted reproduction technology (ART) procedure with ejaculated spermatozoa free of HCV RNA using gradient centrifugation and swim up, due to retrograde ejaculation and severe male factor. ICSI with testicular spermatozoa was the most rational therapeutic approach. The couple was informed about the lack of adequate data on the safety of this therapeutic approach. The risks of this procedure were accepted by the couple. Testicular sperm aspiration combined with ICSI (TESA-ICSI) was performed. After a negative result for an HCV RNA PCR on the embryos' culture medium, four embryos were transferred to the uterine cavity on the third day. The procedure resulted in an ongoing clinical pregnancy, and HCV antibody determinations performed in the mother at the 12th and 24th week of pregnancy were negative. The pregnancy ended at the 39th week due to endo-uterine death. No malformation or hepatic pathologies were found in the conceptus. A second TESA-ICSI cycle is ongoing. This preliminary evidence suggests that, in HCV sero-positive males, ICSI with testicular spermatozoa may be a safe procedure. However, we need more observations to clarify if ART is really able to reduce horizontal and vertical transmission of HCV in sero-discordant couples (only the male infected) in comparison with natural conception.

Female↗
PubMed2001

Plasma factors controlling atrial natriuretic peptide (ANP) aggregation: role of lipoproteins.

We have previously shown that human plasma atrial alpha-natriuretic peptide (alpha-hANP) sequestering is a protective phenomenon against amyloid aggregation. In the present work, the possible role of lipoproteins as alpha-hANP binding factors has been investigated in vitro using an experimental model, developed in our laboratory, that allows to work at physiological concentrations. This approach consists of gel filtration on Sephacryl S-300 HR of big alpha-[(125)I]hANP generated in phosphate buffered saline or in human normal plasma supplemented or not with lipoproteins. The results of these experiments indicate that high density lipoproteins (HDL) are responsible for the ANP binding phenomenon observed in vitro, while low density lipoproteins and very low density lipoproteins do not directly interact with ANP. Moreover, the HDL remodeling process occurring in vitro has been analyzed during plasma incubation by monitoring the redistribution of lipids and apolipoproteins among the HDL subclasses. The changes in HDL size and composition observed in incubated plasma were compared with the redistribution of endogenous and labeled big ANP. The obtained results revealed that both tend to follow the molecular rearrangement in plasma of apolipoprotein A-I containing particles and suggested that, among HDL species, the small particles are mainly involved in the ANP binding phenomenon. This hypothesis was further demonstrated by ligand blotting experiments that confirmed the existence of differences in the ability of HDL particles to bind alpha-[(125)I]hANP.

Atrial Natriuretic Factor↗
PubMed2000

Differences between predicted and observed sequences in Saccharomyces cerevisiae.

We recently studied the protein composition of a Saccharomyces cerevisiae wine yeast strain (K310) of enological interest. About 2,500 spots of 8-250 kDa observed molecular mass were resolved by two-dimensional gel electrophoresis. Experimental molecular masses and isoelectric points were calculated for most of them. Twenty-seven proteins were subjected to Edman microsequencing. N-terminal sequences of 12/27 proteins were determined, whereas internal sequences of 6/27 proteins were obtained following in situ proteolysis. Comparison between the experimental data and those reported in the SWISS-PROT database revealed some differences between genotypic and phenotypic sequences. These are indicative of the changes a protein can undergo with respect to the primary structure coded by the genomic DNA. Our results highlight the need to complement genomic analysis with detailed proteomics in order to refine the vast amount of information provided by DNA sequencing and to find an exact correlation between genome and proteome.

Databases, Factual↗
PubMed2000

Fine structural development of microgamonts of Sarcocystis singaporensis in Python reticulatus.

Three 4-month-old reticulated pythons (Python reticulatus), hatched from eggs laid by a newly caught female from Singapore Island, were fed on muscles of Sarcocystis singaporensis-infected Rattus rattus caught in Singapore. Snakes were sacrificed 5, 6 and 8 days later, the infected tissues were studied by transmission electron microscopy. The present communication summarizes findings on microgamont stages. Both premature and mature microgamonts were already present in the snake sacrificed 5 days post-feeding; young stages, however, were still common 8 days post-infection. Young microgamonts have characteristic, elongated nuclei, which round-up towards the time of microgamete emergence. Microgamonts complete their development within the mucosal epithelial layer; the infected apical epithelial cells undergo degeneration with the loss of the brush border.

Animals↗
PubMed2000

Fine structure of the development of Sarcocystis singaporensis in Python reticulatus from macrogamont to sporulated oocyst stage.

Three, 4-month old reticulated pythons (Python reticulatus) hatched from eggs laid by a newly caught female from Singapore Island, were fed on muscles of Sarcocystis singaporensis-infected Rattus rattus caught in Singapore. Snakes were sacrificed five, six and eight days later. The infected tissues were studied by transmission electron microscope. The present communication summarizes findings on macrogamont and oocyst stages. In the premature stages, rough endoplasmic reticulum consolidate into a large rectangular array; the electron-dense wall-forming-like bodies reveal a laminar structure. Macrogamont parasitophorous vacuoles became filled with granular matrix and electron-dense strands, which later on consolidate into a coat around the fertilized zygote. The oocyst wall is constructed from several formed membranes combined with deposited substance. All development to the sporulated oocyst stage occurs in the mucosal epithelium.

Animals↗
PubMed2000

Validation of the 13C-urea breath test for the diagnosis of Helicobacter pylori infection in children: a multicenter study.

OBJECTIVE: The 13C-urea breath test (13C-UBT) is a safe, noninvasive, and accurate test for the detection of Helicobacter pylori (H. pylori) infection in adults. The aim of this study was to evaluate sensitivity and specificity of 13C-UBT in children using different types of test meal, doses of 13C-urea and breath sampling intervals. As yet, a validated, standardized 13C-UBT protocol for children has not been formulated. METHODS: 13C-UBT was performed in 115 children and repeated within 3 days, modifying the test meal or the dose of 13C-urea. H. pylori status was assessed by histology and rapid urease test. 13C-UBT was performed using 100 mg or 50 mg of 13C-urea and a fatty test meal (100 FA; 50 FA), 50 mg of 13C-urea, and a carbohydrate test meal (50 CA). Breath samples were collected every 10 min for 60 min. RESULTS: The 13C-UBT in children was highly sensitive and specific with all three protocols used. The best combination of sensitivity (97.92%) and specificity (97.96%) was obtained with Protocol 50 FA at 30 min with a cut-off of 3.5 per mil. CONCLUSIONS: The 13C-UBT is an accurate test for the detection of H. pylori infection also in children. Administration of 50 mg of 13C-urea, a fatty test meal, and breath sampling at 30 min appears to be the most convenient protocol.

Adolescent↗
PubMed2000

Peripheral blood neutrophils from hepatitis C virus-infected patients are replication sites of the virus.

BACKGROUND AND OBJECTIVE: Hepatitis C virus (HCV) is able to cause not only acute and chronic liver disease, but also immunologic and hematologic disorders. In order to clarify the extra-hepatic tropism of HCV, and to understand the pathogenetic mechanisms of HCV infection, we evaluated viral replication in peripheral blood mononuclear cells. DESIGN AND METHODS: The presence of genomic and antigenomic (replicative) forms of HCV in B- and T-lymphocytes, monocytes, and polymorphonuclear leukocytes (PML) was determined by reverse transcriptase-polymerase chain reaction in 54 HCV-RNA positive patients and, as control groups, in 10 patients who had recovered from HCV infection without evidence of serum HCV-RNA, and in 10 HCV-negative subjects. RESULTS: In HCV-RNA positive patients, the genomic RNA was found in 94% of B-cells, in 14% of T-cells, in 40% of monocytes and in 77% of PML, while only 1 of the HCV-RNA negative subjects showed positivity in B-cells. The anti-genomic form of HCV-RNA was found in 52% of B-cells, in 3% of monocytes, and in 31% of PML. By contrast, it was never detected in T-cells and in HCV-RNA negative subjects. Neither genomic nor anti-genomic forms were found in HCV-negative cases. INTERPRETATION AND CONCLUSIONS: These data suggest that PML are replication sites of HCV. Whether the infection occurs at the level of the stem cells or subsequently during myeloid cell differentiation is, as yet, unknown. The absence of correlation between the presence of replicative forms and any clinical and/or laboratory data opens the question of the role of HCV replication in extra-hepatic sites.

Adult↗
PubMed2000

[The false myth of toxoplasmosis in salami].

On the basis of available literature concerning Toxoplama gondii infection in swine (swine toxoplasmosis) and the resistance of parasite to heating, freezing, gamma-radiation, salting, seasoning and production processes of "cooked" and "fermented" salami, the possible risk of transmission of the disease from pig (where toxoplasmosis is widely diffuse) to man is discussed. No risk of transmission of the disease, even to children and pregnant women, can derive from the consumption of cooked meat, cooked or salted-fermented salami and ham. The only risk could be related to eating of even small amount of fresh sausages or chitterlings (especially heart, brain and other viscera) and consumption of not drinking water.

Animals↗
PubMed1999

Efficacy and safety of eptastigmine for the treatment of patients with Alzheimer's disease.

OBJECTIVE: To evaluate the efficacy and safety of eptastigmine in patients with moderate to moderately severe AD. BACKGROUND: Eptastigmine is a centrally acting cholinesterase inhibitor. METHODS: The study was carried out according a multicenter, randomized, double-blinded, placebo-controlled, parallel-group design. Patients received a 24-week treatment with placebo or eptastigmine 15 mg or 20 mg three times daily after a 4-week, stepwise dose escalation. The effects of treatment on cognition, global function, and activities of daily living were evaluated with the Alzheimer's Disease Assessment Cognitive Subscale (ADAS-Cog), the Clinician's Interview-Based Impression of Change Plus (CIBIC-Plus), and the Instrumental Activities of Daily Living scale (IADL), respectively. RESULTS: Thirty-six centers recruited 491 patients: 164 on placebo, 166 on eptastigmine 15 mg three times daily, and 161 on eptastigmine 20 mg three times daily. Percentages of patients completing double-blinded treatment were 87% in the placebo group and 86% in both the eptastigmine-treated groups. At the end of treatment, the intent-to-treat analysis on 463 patients showed a dose-dependent effect of eptastigmine on all efficacy variables, with a statistically significant effect of the 20 mg three times daily dose compared with placebo on the ADAS-Cog, CIBIC-Plus, and IADL. Patients on eptastigmine 15 mg three times daily performed significantly better than placebo-treated patients only on the ADAS-Cog. Eleven patients on placebo (7%), 13 patients on eptastigmine 15 mg three times daily (8%), and 12 patients on eptastigmine 20 mg three times daily (8%) discontinued study treatment because of adverse events. Adverse events were recorded in 49% of patients on placebo compared with 54% on eptastigmine 15 mg three times daily and 48% on eptastigmine 20 mg three times daily. Cholinergic side effects (nausea, vomiting, diarrhea, and abdominal pain) were reported with similar frequency in the eptastigmine- and placebo-treated patients. There was a dose-dependent transient and mild neutropenic effect associated with eptastigmine treatment, and one patient on 20 mg three times daily had an asymptomatic pancytopenia. CONCLUSIONS: Eptastigmine produces significant cognitive, clinical, and functional benefits in patients with probable AD. Although the cholinergic tolerability of eptastigmine was found to be favorable, its potential adverse hematologic effects limit its clinical utility.

Aged↗
PubMed1998

Seroprevalence to bovine immunodeficiency virus and lack of association with leukocyte counts in Italian dairy cattle.

We report herein on the first serological detection of antibodies to bovine immunodeficiency virus (BIV) in Italy. According to criteria of a stratified-random sampling of dairy cattle reared in the Parma area (a province in the Po Valley, Northern Italy), sera from 3166 cows belonging to 272 herds were collected. In addition, sera of 138 bulls from eight artificial-insemination (AI) centres were sampled. Seventy-eight cows (2.5%) from 16 herds (5.8%) and seven bulls (5.1%) from two AI centres were positive for BIV-R29 antibodies in the IFA-test. IFA-positive sera assayed by Western blot had reaction to different viral proteins: 81 out of 85 sera showed antibody to p26 (considered the BIV major internal core protein); four sera reacted to other viral proteins but not to p26. Peripheral blood leukocytes of 60 seropositive and 60 seronegative animals, belonging to eight BIV-infected herds, were enumerated to assess any effect of BIV infection on white-blood cells. No significant differences were detected between the two groups. These data indicate that BIV infection is present in Italian dairy cattle--but the role of BIV in inducing disease remains unclear.

Animals↗
PubMed1998

Assessment of anti-PGL-I as a prognostic marker of leprosy reaction.

The anti-phenolic glycolipid-I (PGL-I) assay as currently applied for leprosy is conceived as an early marker of asymptomatic infection, early disease diagnosis and cure monitoring. Its use as a prognostic marker of reaction is still a matter of controversy. We conducted a case-control study to investigate whether IgM and IgG anti-PGL-I antibodies could discriminate patients at increased risk of developing reactions. Eligible cases were untreated leprosy patients at the onset of type 1 and type 2 reactions recruited from among 600 concurrent, newly detected, untreated leprosy patients attending an outpatient clinic in central Brazil. For the patients with reaction, approximately the same number of leprosy cases without reaction matched as to bacterial index (BI), age and gender were randomly selected. Individuals without clinical leprosy were evaluated as healthy controls. Sera from type 1 reaction (N = 43) and type 2 reaction (N = 26) patients were tested by an ELISA using PGL-I synthetic disaccharide-BSA antigen and 1:300 sera dilution (cut-off point > or = 0.2 OD). Antibody profiles were evaluated by exploratory data analysis and reverse cumulative distribution curves. The IgG anti-PGL-I response did not have a defined pattern, being detected only at low levels. Our results indicate that leprosy patients, independently of their reactional status, produce high levels of IgM anti-PGL-I, demonstrating a strong correlation between the magnitude of antibody response and the BI. Patients with a higher BI were at least 3.4 times more prone to produce an antibody response compared to healthy controls.

Adult↗
PubMed1997

[Nasal surfactant: biochemical and histological study].

The existence of a Surface Tension Lower Substance (STLS) in the lung and the Eustachian tube was established a few decades ago. The histological and physiological characteristics of the epithelium of the whole respiratory tract, from the nasal cavities to rhinopharynx and bronchiolar segments, induced the Authors to search for such a similar substance also in nasal secretion. To this purpose nasal secretions were studied using High Pressure Liquid Chromatography (HPLC) to determine the presence of phospholipids. In addition, ultrastructural examination of the nasal mucosa was performed looking for lamellar body-like structures of 2nd degree pulmonary cells.

Humans↗
PubMed1996

Identification of a novel RalGDS-related protein as a candidate effector for Ras and Rap1.

Although Ras and Rap1 share interaction with common candidate effector proteins, Rap1 lacks the transforming activity exhibited by Ras proteins. It has been speculated that Rap antagonizes Ras transformation through the formation of nonproductive complexes with critical Ras effector targets. To understand further the distinct biological functions of these two closely related proteins, we searched for Rap1b-binding proteins by yeast two-hybrid screening. We identified multiple clones that encode the COOH-terminal sequences of a protein that shares sequence identity with RalGDS and RGL, which we have designated RGL2. A 158-amino acid COOH-terminal fragment of RGL2 (RGL2 C-158) bound to Ras superfamily proteins which shared identical effector domain sequences with Rap1 (Ha-Ras, R-Ras, and TC21). RGL2 C-158 binding was impaired by effector domain mutations in Rap1b and Ha-Ras. Furthermore, RGL2 C-158 bound exclusively to the GTP-, but not the GDP-bound form of Ha-Ras. Finally, coexpression of RGL2 C-158 impaired oncogenic Ras activation of transcription from a Ras-responsive promoter element and focus-forming activity in NIH 3T3 cells. We conclude that RGL2 may be an effector for Ras and/or Rap proteins.

3T3 Cells↗